OverviewThe Fitzgerald Creek Water Pollution Control Facility is

owned by the Cherokee County Water and Sewer Authority

(CCWSA) and located in the City of Woodstock, GA. The water

reclamation facility became operational in 1988 and occupies

a 50-acre campus about 30 miles NW of metropolitan Atlanta.

It is permitted to treat 6.25 million gallons per day (MGD) and

processes between 3 MGD and 5.9 MGD, with an average

daily flow of 5.0 MGD of primarily municipal wastewater. The

facility also receives wastewater from an industrial facility - a

poultry processing plant.

Challenge The original biological treatment process at Fitzgerald Creek

utilized a combined extended aeration biological (sequencing

batch reactor) system operating in the Intermittent Cycle

Extended Aeration System (ICEAS) modified process (react-

settle-decant). However, with increasing population trends

and facing tighter nutrient regulations on the horizon, the

CCWSA made a strong commitment to not only meet their

anticipated discharge permit of 0.14 mg/L P, but consistently

achieve <0.07 mg/L. In search for the right technology to assist

with this venture, a technology and manufacturer evaluation

process was put into place, and in 2001, plans to develop the

best post-SBR treatment began.

Two of Parkson’s Trusted Technologies Combine to Provide an Enhanced Nutrient Removal Advantage to Protect Our Waterways

CASESTUDYLamella®, DynaSand®

City of Woodstock, GA

SolutionCherokee County conducted an extensive on-site pilot

evaluation of several available process options and

technologies, including various plate settler designs. Parkson

(Ft. Lauderdale, FL) was selected as the preferred technology

provider and piloting began in 2001.

Several treatment options were evaluated, including plate

pack settler only, DynaSand® continuous backwash filter

only, and plate pack settler integrated with DynaSand

filtration. Ultimately, the integrated design delivered the best

results and far exceeded the technical performance criteria

of 0.14 mg/L P, 100% of the time. The technical evaluation

team and Parkson lead team then selected the combined

enhanced nutrient removal (ENR) integrated design option,

achieving <0.07 mg/L P, and designed to discharge into

Little River directly. This included Parkson’s technologies –

Lamella® Gravity Settler in the plate pack configuration and

DynaSand® deep bed filtration utilizing continuous backwash

for overflow polishing.

One benefit of Lamella clarification is that it requires a

significantly smaller footprint when compared to conventional

clarifiers. The inclined plate settling area equals the plate’s

area projected on a horizontal surface with up to 10 square

feet of settling area available for each foot of land (or floor

space) occupied by the unit. Additionally, with Parkson’s

EcoFlow® technology, which allows for 100% plate utilization,

a further 25% size advantage can be realized over other

designs. When operating at optimized chemical treatment

using PACL, Lamella provided a design loading rate of 0.30

gpm/ft2.

Clarified water essentially free of TSS and >91% less P is

then directed to Parkson’s DynaSand deep bed continuous

backwash sand filter. EcoWash® can be added to allow for

reduced reject, higher energy efficiency and lower backwash

volume - as much as 60-90% over traditional backwash

systems - all while improving filtrate quality. Additionally,

EcoWash uses a reliable PLC-based sand movement

detection system that is tied to an alarm and can be monitored

in the main control room. Typical final effluent concentrations

for ammonia, phosphorus and turbidity leaving the final

polisher and entering the Little River are shown in Table 1.

Final ef� uent trough with V-notch ef� uent weir

Plate pack and sludge rake mechanism

Table 1: Fitzgerald Creek WTF Effluent Quality

Target Average

Ammonia (mg/L): 0.5-1.0 <0.05

Phosphorus (mg/L): <0.14 <0.06

Turbidity (NTU): <2.0 <0.30

* Effluent empties directly into the Little River. Final water quality exceeds

national discharge permit limits on these powerful nutrients that impact

aquatic environments negatively, even at small concentrations.

Fitzgerald Creek Facility Operation Fitzgerald Creek’s headworks consists of screens and flow

equalization tanks that pre-condition and flow equalize the

raw wastewater. Raw municipal water is then conveyed

to four basins utilizing an extended aeration SBR process.

The operational parameters are geared towards younger

biology and low-end HRT to ensure highest biodegradation

efficiency at high sequence rates of <10 days. The F:M ratio

is maintained at 0.05-0.07. The basin SBR DO is maintained

between 3-4 mg/L.

SBR overflow is decanted to a pit preceding the Lamella

gravity settler basins. The overflow first enters a flash mixing

compartment where 140 mg/L-160 mg/L PAC is introduced

under agitation for particle agglomeration and to enhance

settling characteristics. Post agglomeration, 1-2 mg/L of

anionic polymer is fed to flocculate the solids.

Chemically conditioned wastewater is then directed via gate

valves to four Lamella settler basins each having four sets

of Lamella plate packs. Each Lamella basin serves as a

secondary clarifier where agglomerated and flocculated raw

water solids settle onto inclined plates per basin. Solids that

settle into the plates eventually drop to the bottom where

a rotating assembly pushes the solids towards a central

location to be pumped out. All solids are directed to the onsite

digesters for further treatment.

Overflow is directed to a series of Parkson’s DynaSand deep

bed filter modules by gravity. The integrated LGS-DSF design

is an enhanced nutrient removal process recognized for its

superior ability to treat municipal water and wastewater to a

final effluent quality that exceeds NPDES quality standards

for surface water nutrients such as TSS, Turbidity and N &

P. The Lamella Gravity Settler was equipped with EcoFlow®

technology. Parkson’s patented EcoFlow design, which allows

100% plate surface area utilization, is a true advancement

over prior plate configurations where only 80% of the plate

area was available for settling. Its benefits are unmatched in

its peer group for plate efficiency and performance and allows

for superior particle capture at higher flows.

FEED RADIALS (C)

AIRLIFT HOUSING (N)

UPWARD FLOWING

FILTRATE (M)

SAND WASHER (I)

TOP OFAIRLIFTPIPE (G)

FILTRATE WEIR (J)

DOWNWARD MOVING

SAND BED (D)

INFLUENT ANNULARS (B)

BOTTOM OF AIRLIFT

PIPE (F)

REJECT COMPARTMENT

(H)

REJECT WEIR (K)

REJECT PIPE (L)

INFLUENT PIPE (A)

EFFLUENT PIPE (E)

Table 2: SBR Operating Parameters

SBR Operating Parameters Range

DO (react only) 3 to 4 mg/L

pH 6.7 to 7.1

F:M 0.05 to 0.07

Actual SRT 6 to 10 days

Cross-sectional view of DynaSand internals

Fort Lauderdale

Chicago

Kansas City

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Dubai

1.888.PARKSON

technology@parkson.com

www.parkson.com

To complete the enhanced nutrient

removal process, Parkson’s continuous

backwash DynaSand filter system was

added after the Lamella settler. An

added benefit of using the single-stage

deep-bed DynaSand filter system is

its capability to be upgraded in the

future to meet low Total Nitrogen (TN)

limits. The DynaSand fiiltration system

has the ability to simultaneously

remove both N and P in the same filter

with the addition of a supplemental

carbon source and operated as a

denitrification filter.

Results Piloting concluded in 2008. Since then, the Parkson enhanced

nutrient removal (ENR) integrated design continues to deliver

water quality of <0.1 mg/L Ammonia, <0.07 mg/L Phosphorus

and <0.5 NTU. Not only does the Fitzgerald Creek WWTP

consistently meet EPA direct discharge limits on BOD, Total

Nitrogen, Phosphorus and Turbidity, but these final effluent

values readily exceed Fitzgerald Creek’s surface water

discharge permits levels.

Table 3: Final Water Quality- Data to Little River

Water Quality Parameter Lamella Feed Post Lamella PP Post DynaSand SF

TSS >50 mg/L <5 mg/L <2 mg/L

Ammonia 0.05 to 0.5 mg/L NA 0.04 to 0.09 mg/L

Phosphorus 1 to 3 mg/L 0.04 to 0.17 mg/L 0.03 to 0.07 mg/L

Turbidity 15 to 20 NTU 0.5 to 1.5 NTU 0.1 to 0.3 NTU

Plant operators have been very pleased with performance of

the system and even received recognition as the 2015 Water

Reclamation Facility of the Year by the Georgia Association of

Water Professionals in the category of Advanced Treatment.

This distinguished plant consistently exceeds their NPDES

(National Pollutant Discharge Elimination System) surface water

discharge permit on nutrients 100% of the time.